It is known in elevator systems to use touch button switches for hall call switches by means of which passengers call elevators for service at a floor of a building, as well as for car call buttons by means of which passengers within the elevator select a floor at which they wish the car to stop. The call buttons may either comprise tactile switches, which cause transfer of a switch armature from a normally open to a normally closed position, with or without a noticeable spring response, or they may be motionless, such as are operated by interaction with capacitance effects of a human body member. Early call buttons included a lamp to illuminate the entire touch pad following actuation of the switch, in order to provide an indication of response to the passenger. More recently, rings of light-emitting diodes (LEDs) have been used to illuminate a ring surrounding the touch pad in order to provide the response indication.
On the one hand, many building designers and other elevator customers demand motionless, such as capacitive, touch buttons for use as elevator call buttons because of the aesthetics--the architectural elegance associated with lack of motion. However, the capacitance effect of a motionless touch button is not satisfied if the user does not make good electrical contact with touch pad, which occurs frequently when the users are wearing gloves. Furthermore, depending upon the application and the locality, motionless touch buttons violate safety codes in many cases. This is principally because of the need for visually handicapped persons to achieve a non-visual response as assurance that switching has occurred as a consequence of having touched the touch button. Therefore, tactile response is frequently required, which is most often satisfied with mechanical switches. In crowded elevator cars, the visual response provided by lighting the touch pad or a ring around the touch pad is frequently obscured by other passengers. Because of these conflicting requirements, it is common therefore to have a single elevator model or style of elevator cab and operating panel to be provided with different touch buttons, depending on the nature and location of their intended use. This further requires having two different types of touch button spare parts in inventory for maintenance.
Touch buttons of the prior art have been relatively quite expensive, either having complex mechanisms to accommodate microdot switches or the like, or having large circuit boards to accommodate motionless (for instance, capacitance) actuation. While many improvements have been made in touch buttons of the type used in elevators, many of the aforementioned difficulties remain. A touch button of this type is disclosed in U.S. Pat. No. 5,039,832.